package org.bouncycastle.jce;

import java.io.IOException;
import java.security.cert.CRLException;
import java.security.cert.CertificateEncodingException;
import java.security.cert.X509CRL;
import java.security.cert.X509Certificate;

import org.bouncycastle.asn1.ASN1Object;
import org.bouncycastle.asn1.x509.TBSCertList;
import org.bouncycastle.asn1.x509.TBSCertificateStructure;

/**
 * a utility class that will extract X509Principal objects from X.509
 * certificates.
 * <p>
 * Use this in preference to trying to recreate a principal from a String, not
 * all DNs are what they should be, so it's best to leave them encoded where
 * they can be.
 */
public class PrincipalUtil {
    /**
     * return the issuer of the given cert as an X509PrincipalObject.
     */
    public static X509Principal getIssuerX509Principal(X509Certificate cert)
            throws CertificateEncodingException {
        try {
            TBSCertificateStructure tbsCert = TBSCertificateStructure
                    .getInstance(ASN1Object.fromByteArray(cert
                            .getTBSCertificate()));

            return new X509Principal(tbsCert.getIssuer());
        } catch (IOException e) {
            throw new CertificateEncodingException(e.toString());
        }
    }

    /**
     * return the subject of the given cert as an X509PrincipalObject.
     */
    public static X509Principal getSubjectX509Principal(X509Certificate cert)
            throws CertificateEncodingException {
        try {
            TBSCertificateStructure tbsCert = TBSCertificateStructure
                    .getInstance(ASN1Object.fromByteArray(cert
                            .getTBSCertificate()));
            return new X509Principal(tbsCert.getSubject());
        } catch (IOException e) {
            throw new CertificateEncodingException(e.toString());
        }
    }

    /**
     * return the issuer of the given CRL as an X509PrincipalObject.
     */
    public static X509Principal getIssuerX509Principal(X509CRL crl)
            throws CRLException {
        try {
            TBSCertList tbsCertList = TBSCertList.getInstance(ASN1Object
                    .fromByteArray(crl.getTBSCertList()));

            return new X509Principal(tbsCertList.getIssuer());
        } catch (IOException e) {
            throw new CRLException(e.toString());
        }
    }
}
